watercolor value study

original sketch

 A little value study for a watercolor painting.  It is based upon a photo I took of a tree in Savanah, GA.  In the past I've avoided working from photos.  It is, however, far more convenient to work from a photo rather than from life.  My goal is to learn how to use them without merely reproducing the photo as is.
Next I have to determine my color palette.  I'm thinking I will go with a very green, spring-like color scheme.

converted to sepia tones

the photo I'm working with